There are plenty of channel and North Sea ports allowing easy passage of goods from the continent to the UK. The Dutch and Belgian ports would love to lift more of the Calais-Dover trade. Calais has made quite clear it wants to keep the trade. No need to worry. There will be plenty of imports coming in on 30 March after we have left. Remember, the UK government will decide what checks to have at Dover! No need to delay them. They mainly come in already inspected, checked and logged electronically away from the border.